ntpd fails to start if terminals are closed before ntpd's child process can open new fds. Testing with HAVE_CLOSEFROM in config.h doesn't have this issue. Before restrarting ntpd from A: $ ntpq -pn remote refid st t when poll reach delay offset jitter ============================================================================== north-america.p .POOL. 16 p - 64 0 0.000 0.000 0.002 *50.22.155.163 209.51.161.238 2 u 1 64 1 87.964 -2.998 2.572 ... Using something like the following to restart ntp on an array of machines: for m in A B C; do ssh -t "$m" 'sudo service ntpd restart' ; done Later from host A: ... Dec 23 18:40:57 <ntp.notice> A ntpd[80966]: ntpd 4.2.8p9-a (1): Starting ... $ ntpq -pn ntpq: read: Connection refused ... ntpd fails to finish starting up and silently fails. The same is true from B and C. Running the same without ssh's -t or sleeping before the connection closes allows ntpd child to startup. This assumes the user can run sudo without a password: for m in A B C; do ssh "$m" 'sudo service ntpd restart' ; done or for m in A B C; do ssh -t "$m" 'sudo service ntpd restart; sleep 1' ; done Testing ntpd from the relang/11.0 branch with '#define HAVE_CLOSEFROM 1' in config.h appears to solve the problem. This will cause libntp/ntp_worker.c close_all_beyond() to use closefrom(2) that appears to not suffer the same issue as the two other ifdef's. However, the issue appears to be contrib/ntp/ doesn't have a test to see if the system has closefrom(2) so it appears we have to add it manually? This was initially found when restarting ntpd on a legion of machines via ansible. I'd suspect other config management tools that use ssh with pseudo-terminals would suffer the same issue. The above is a raw example of what something like ansible might perform. This is also a problem in 9.3 and 10.x